%
% interp_matrix_p.m
%
%   Form the interpolation matrix for the pressure
%   which is stored at the cell centers; use constant
%   interpolation
%
%   input -- Nx number of cells in x-direction, fine grid
%            Ny number of cells in the y-direction, fine grid
%   output
%
function Ip = interp_matrix_p_const(Nx,Ny);

% form two one-dimensional interpolation matricies
%
Ipx = cc_nm_interp1_const(Nx);
Ipy = cc_nm_interp1_const(Ny);

% assemble the matrix for the two-dimensional problem
%   note the y-x ordering in kron, this correpsonds to 
%   the case when the first index is for the x-coordinate
%
Ip = kron(Ipy,Ipx);

